src: remove unused headers in src/util.h

PR-URL: #33070
Reviewed-By: James M Snell <jasnell@gmail.com>
Reviewed-By: Anna Henningsen <anna@addaleax.net>
Reviewed-By: Sam Roberts <vieuxtech@gmail.com>

Author: juanarbol

src/util.h

@@ -33,9 +33,7 @@
 #pragma GCC diagnostic pop
 #endif
 
-#include <cassert>
-#include <climits>  // PATH_MAX
-#include <csignal>
+#include <climits>
 #include <cstddef>
 #include <cstdio>
 #include <cstdlib>